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Title: Slide sem t


1
Interactive Television
Multimedia in the 21st Century
Takashi Tome
Jun/2001
2
Interactive Television
  • Contents
  • Basic concepts
  • Interactive Television
  • Local interactivity
  • One-way interactivity
  • Two-way interactivity
  • Some issues

3
Concepts
ITU-T J.110 ITU-R BT.1369
Television set
Broadcast service provider
Broadcast channel
RDU - receiver decoder unit STB - set top box,
navigation device, IRD - integrated receiver
decoder
Forward interaction path
Interaction channel
Interactive service provider
Return interaction path (or channel)
4
Concepts
ITU-T J.110 ITU-R BT.1369
Television set
5
Broadcast
Over-the-air broadcasting
6 MHz channel
Return via PSTN or mobile
6
MMDS
MMDS in Brazil
Broadcast channel 15 to 31 x 6 MHz
Return channel 2.170-2.182 MHz
7
Cable
Cable TV network
Broadcast channel forward path 54 to 540, 750,
860, 1000 MHz
Return path 5 to 3545 MHz
8
Concepts
A MPEG-2 System
9
Concepts
  • What is Interactive Television?

10
Local interactivity
Local Interactivity (Enhanced broadcasting) All
information is broadcasted, and the user
navigates locally through data stored in the
set-top box.
Interactive service provider
11
Local interactivity
  • EPG - Electronic Programming Guide
  • IPG - Interactive Programming Guide
  • Search programs (channels)
  • Set preferences and filters
  • Program in advance (timer functions)
  • Parental control
  • Navigation through locally stored information
  • Local processing of keywords
  • Could send command messages to VCR or TV
    through STBs interfaces

12
Local interactivity
  • Data broadcasting
  • Data carousel, object carousel, virtual channel
  • Weather
  • Economic data
  • Community interest news
  • Navigation through locally stored information
  • Local processing of user commands

www.climatempo.com.br
13
Local interactivity
  • Personal VCR
  • ReplayTV (Panasonic), TiVo (Sony, Phillips)
  • Record programs
  • On screen menu
  • Intelligent functions to search and record
    programs

TiVo is more than a simple PVCR it has, in
fact, a 2-way interaction channel
14
One-way interactivity
One-way interactivity (Interactive
broadcasting) Return path is used to place orders
15
One-way interactivity
  • Pay-per-view
  • User acquires a credit to watch a given amount
    of programs, or pays after watching
  • Users choose programs to pay-per-watch through a
    TV menu
  • The order and credit card number are sent
    through return path
  • Encoded programs are delivered to users with
    scrambling keys
  • Program on demand
  • Replay of TV programs showed on the same day (or
    some days before)
  • Schedule defined by the rate of orders
  • May be paid or free

16
Two-way interactivity
Two-way interactivity (Internet access profile) A
two-way interactive channel (in-band or
out-of-band) is used for bidirectional
communication between user and service provider
Interactive service provider
17
Two-way interactivity
Internet access e-Mail Pizza on demand
(Home-shopping)
Internet access server
  • Can provide
  • full access to the Internet cloud, or
  • emulate a small portal with a handful set of
    sites (restricted community)
  • e-mail

18
Cultural issues
  • Display definition
  • PC 640x480 (VGA), 800x600 (SVGA)
  • Analog TV approx. 330x300 (can think as
    320x240)
  • Viewing distance
  • PC 3060 cm
  • TV gt 1 m
  • Therefore
  • Dont use small fonts or details
  • Scroll bars also difficult to handle

19
Two-way interactivity
Internet access
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Internet access server
Modified page
Ex Microsoft TV (WebTV), WorldGate
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Set top
20
Two-way interactivity
  • TV PC
  • Dual window, WebSync
  • Join a streaming video with internet pages

21
Two-way interactivity
Video-on-Demand
MPEG-2 pipes inside broadcast channel
Video server Ex DIVA, SeaChange, Aerocast
22
Transmission issues
A 6 MHz-channel standard transport stream 19
Mbit/s May transport 4 SDTV programs some
data A VoD program 1 SDTV ( 4 Mbit/s) An
internet access averaged 50kB per page
(400kbit), 1 page change per minute 6.7
kbit/s 4 Mbit/s 600 users How many users
can you serve simultaneously? Need to think a
better Business Model
23
Rethinking the way we do it
A linear program
Begin
End
24
Two-way interactivity
A truly interactive television program
25
Software issues API
The same program (application) written (with
differences) to HW-a and HW-b.
Games, e-ciclopaedias, t-commerce
HARDWARE and OS - a
HARDWARE and OS - b
26
Software issues API
API - Application Program Interface - provides an
uniform interface to application programs, hiding
hardware specifics.
Games, e-ciclopaedias, t-commerce
API for HW/OS-b
API for HW/OS-a
HARDWARE and OS - a
HARDWARE and OS - b
27
Software issues API
  • Some APIs
  • OpenTV
  • WorldGate
  • Mediahighway
  • PowerTV
  • DTV Navigator
  • Betanova
  • Microsoft TV
  • MHP

28
Software issues API
Common internet-style files
Any program written in C/C, Pascal,
VisualBasic, etc.
API
HW OS
29
Software issues API
Common internet-style files
Any program written in C/C, Pascal,
VisualBasic, etc.
Code/script interpreters internet browser,
Java Virtual Machine, plug-ins
API
HW OS
HW
30
Hardware issues
Static Processor A typical architecture
Optimized for shared multitasking
31
Hardware issues
Static Processor
Cache
Main memory status
Data stream
Instruction stream
Some amount of data
Instruction cache
Data cache
Instructions (more or less huge program)
CPU
Ex a word processor
32
Hardware issues
Dynamic Processor A typical architecture
Cache for time-synchronizing needs only
Optimized for Real-Time (image processing)
applications
33
Hardware issues
Dynamic Processor
Cache
Main memory status
Data stream
Instruction stream
Huge amount of data
Instruction cache
Data cache
Small amount of instructions
CPU
Ex a 3D video-game
34
Hardware issues
  • Typical Set-Top Box
  • Static type processor architecture
  • 4 8 MB RAM
  • 4 to 8-bit graphics overlay capability
  • High-end Set-Top Box
  • Static type processor architecture
  • 14 90 MB RAM
  • 32 bit graphics overlay (true color)
  • 64 bit bus
  • To the Future
  • How to converge todays PC-like memory-hungry
    applications (.exe) and huge-amount-of-data type
    real time ITV applications?

Example of memory usage an HTML page 10 - 100
k EPG 300 - 400k Microsoft platform 6 M RAM
35
Conclusion
  • Interactive Television is more than a television
    with clickable interface and return channel.
  • We must change the way we think television
    programs, from linear programs to non-linear
    ones (technological and cultural issues).
  • How can we have a boom of interactive television
    content production similar to that happened in
    the internet?
  • Is the current set-top-boxs hardware
    architecture suited for future interactive
    television programs?

36
Conclusion
With Interactive Television, sky is the limit...
...and theres a lot of things to do.
Take this flight !
37
Bib Ref
Some useful references 1 ITU-R Rec J.110 Basic
principles for a worldwide common family of
systems for the provision of interactive
television services, 1997-1998 2 ITU-T Rec.
J.111 Network independent protocols for
interactive systems 3 ITU-T Rec. J.112
Transmission systems for interactive cable
television services 4 ITU-T Rec. J.90
Electronic programming guides for delivery by
digital cable television and similar
methods 5 Advanced TV Enhancement Forum
www.atvef.com 6 Digital Audio Video Interactive
Council www.davic.org 7 DVB Multimedia Home
Platform, www.dvb.org 8 Microsoft TV Platform
(WebTV) www.microsoft.com/TV 9 Motorola
Broadband (GI) www.motorola.com/broadband 10
Scientific Atlanta www.sciatl.com 11
SeaChange www.schange.com 12 CPqD
www.cpqd.com.br/produtos/dotip 13 Fluckiger, F
Understanding Networked Multimedia, Prentice Hall
38
MUITO OBRIGADO Thank you Merci
takashi_at_cpqd.com.br
http//www.cpqd.com.br
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